“…Continuum-space models started earlier with the seminal work by Hughes (2002), and are typically formulated as a system of two partial differential equations (PDE), a two-dimensional (2-D) conservation law for the density, ρ, coupled with a PDE for the route choice, typically of the Eikonal or Hamilton-Jacobi type, either for vehicular traffic (see e.g., Jiang et al, 2011, Du et al, 2013, Lin et al, 2017 or for pedestrian flow (see e.g., Huang et al, 2009a,b, Jiang et al, 2009, 2010, 2012, Hoogendoorn and Bovy, 2004, Hoogendoorn et al, 2015.…”